As the breadth of biometric identification implementations grow across a variety of sectors, fingerprints continue to be a critical source for establishing identity. Latent prints are prints that remain after an individual has left the scene where the prints are found. Tenprint is a term of art describing a complete set of prints that is intentionally captured using ink on fingerprint cards, a live scanner or similar methods where the individual is present as the prints are obtained. The term tenprint is used herein to refer generally to a reference prints or prints, whether or not it comprises a complete print, a partial print or set of prints, and the term latent print is used to refer generally to a print that is to be compared to a reference print or prints.
Many latent fingerprints do not provide a practical basis for identification using conventional approaches. Matching latent prints with corresponding exemplars requires highly skilled human expertise. Under current practice, Latent Fingerprint Examiners determine that many prints have no identification value due to the limited quantity and quality of their friction ridge information. This class of prints with insufficient “minutiae” to support identification is referenced as NIV (No identification Value) latent prints. The automated matching of partial latent prints against reference prints is often, with conventional methods, an unsolved problem. Conventional fingerprint searching requires that a latent print contain a sufficient number of minutiae (ridge bifurcations and terminations) to support searching. Without enough minutiae, searching cannot be performed. Thus, the inventors have determined that there is a need for an automated method that can work with information presented within latent prints beyond traditional minutiae.
Paper-bound prints represent one of the most challenging aspects of the general latent fingerprint problem because the paper absorbs the oils and amino acids that comprise the print. The result is a print that is very difficult to capture as an image coupled with an image that is to “coarse” for processing by Automated Fingerprint Identification Systems (AFIS) technology.
Paper documents provide a wealth of information related to identity. If the documents are handwritten or bear a signature, the identity of the writer can be discovered through the individualistic characteristics within the handwriting. Another major source of identity takes the form of fingerprints. The longstanding problem with extracting fingerprints from paper documents has been that the methods needed to reveal the fingerprints are destructive to the document. The problem is further compounded by the fact that fingerprints extracted from paper documents tend to be of low quality due to the textured nature of the background paper.
Furthermore, isolating prints on paper documents is time consuming process requiring technical expertise both in the capture of prints and extracting the minutiae information from the prints necessary to perform an automated search against a fingerprint database.
Using prior art methods, a fingerprint is “developed” from underlying paper. This process requires chemical treatment of the paper and takes several minutes to perform for a single page. The result is damage to the underlying document. Furthermore, an expert is required to identify the minutiae within the print that can be used as the basis for an automated search. The quality of fingerprints extracted from paper is often much poorer than those captured directly from fingers. The inventors have determined that there is a need for an improved method of processing fingerprints on paper items and using them for identification.
The discussion of prints on paper provided herein is but an example of an entire class of latent fingerprints that lacks sufficient information to be identified automatically by conventional minutiae-based methods. Other examples include latent prints where the surface contact area is extremely small leaving only a small fraction of the finger surface as the actual print; prints deposited on three dimensional surfaces such as pencils and cups; prints where information is missing due to deterioration or, in the case of tenprints captured in ink on fingerprint cards, image distortion due to too much or too little ink; and parts of the finger such as sides and fingertips which can also deposit prints with limited minutiae displayed. Finally, the advent of small portable devices such as smart phones creates an opportunity to use fingerprints as a means of establishing user identity for security purposes and to structure a “user experience” that best reflects individual preferences. To make such a capability fit within the “usual and customary” use of the device and without requiring an overt action by the user to provide a fingerprint specimen, it will be necessary to capture areas of the print such as the fingertips, sides and/or small surface fragments that have sufficient information to identify the user.
The inventors have developed new systems and methods that address these and other needs and issues in the industry.